Intensive researches have been made to improve the efficiency and performance of internal combustion engines for vehicles. Modern direct injection type engines include a spark plug, multiple valves, and a fuel injector located inside the combustion chamber so that the fuel is injected into the cylinder directly, as disclosed in Korean Patent Application Publication No. 1997-112281 and Japanese Patent Application Publication No. 2002-51618. In most of the modern direct injection type engines, an engine computer calculates a timing and an amount of fuel (or fuel/air mixture) to be injected to the combustion chamber on the basis of sensed operating conditions and parameters.
One of the obstacles in providing higher efficiency and performance vehicle engines is spatial limitations for the multiple valves, fuel injector and spark plug.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.